Objectives • The students will be able to identify different minerals, colors, sizes, and textures that appear in most intrusive igneous rocks.
Igneous Rocks • The word igneous comes from the Latin word ignis, which means "fire". • Igneous is used to describe rocks that crystallize out of hot molten material in the Earth called magma. • When magma pushes up through Earth's crust to the surface, it is called lava. Both magma and lava cool and harden to form igneous rocks.
Intrusive vs. Extrusive • Made from magma. • Cools inside the Earth. • Cools slowly, allowing large crystals to form. • Crystals can usually be seen by the unaided eye. • Made from lava. • Cools on the Earth’s surface. • Cools quickly, forming small crystals. • Need a magnifying devise to see crystals. Intrusive = In Extrusive = Exit Obsidian Granite
Types of Minerals How can you tell how many minerals are in a rock? Just by looking at them! 3.) Mafic Minerals Darker minerals Colors include: black, brown, dark gray, or green They have a lot of iron and magnesium in them 4.) Ultramafic Minerals Dark colors and can have some green Less than 45% silica Has lots of iron and magnesium in them 1.) Felsic Minerals • They are light in color • Colors include: gray, white, pink, or colorless • They have more silica than any other mineral 65%+ 2.) Intermediate Minerals • Darker than Felsic, but lighter than Mafic • 55%-65% of the mineral is silica • Granodiorite (Granite)
Physical Characteristics Intrusive rocks have large crystals that can be seen with the naked eye. A rock with large crystals is coarse-grained
Physical Characteristics Igneous intrusive rocks can be…. Felsic(Light colored)- Minerals are often colorless, white, gray or pink And Mafic(Dark colored)- Minerals are chiefly black, brown, dark gray and sometimes green
Other Important Intrusive Rocks Gabbro • This rock is the equivalence of a Basalt which is in extrusive rocks. • Coarse grained rock Granite • Medium coarse grained rock • How are they made? • When molten magma is stuck underneath the Earth’s surface, it begins to cool and crystallize.
Uses of Igneous rocks Buildingmaterials Counter tops (kitchens, bathrooms)
Curling stones-Thick stone disc with handle (40lbs.) used for a sport played on ice. Marbles
Works Cited • Gabbro. (2010, December 3). Retrieved January 23, 2011, from Wikipedia: http://en.wikipedia.org/wiki/Gabbro • Granite. (2011, January 18). Retrieved January 23, 2011, from Wikipedia: http://en.wikipedia.org/wiki/Granite • Hamilton, C. &. (2011). Igneous Rocks. Retrieved January 23, 2011, from scienceviews.com: http://www.scienceviews.com/geology/igneous.html • Vogel, C. G. (2000). Science Explorer Inside Earth. Upper Saddle River, New Jersey: Prentice Hall. • Galleries, A. (2011, January 21). The Rock. Retrieved January 18, 2011, from Amethyst Galleries: http://www.galleries.com/rocks/granite.htm